Network packet routers use buffer management techniques to share limited buffer space between various incoming data ports and classes of data packets. Typically, the packets are divided into cells that are managed by a set of queues. Packets from multiple ports are en-queued to multiple queues based on their classified priority and de-queued based on available bandwidth of the shared output port(s). Often the available output bandwidth is less than the aggregate input bandwidth and packets must be dropped because there is limited shared buffer memory. Packets are dropped by either not en-queuing them at the tail of the queue for processing, or by de-queuing from the head of the queue and simply not processing them. If there is efficient buffer management of the shared buffer memory, overall loss performance can be improved, i.e., the packet drop rate can be minimized. However, there are many restrictions on implementing a buffer management scheme. The hardware implementing the management should operate at the rate of the incoming packets, and this rate approaches the maximum rate that can be realized using current memory technology.
Routers use buffer allocation techniques to share limited buffer space between various incoming data ports and classes of data packets. Packets from multiple ports are en-queued to multiple queues based on their classified priority and de-queued based on available bandwidth of the shared output port(s). To ensure that higher priority traffic receives a guaranteed share of the buffer space, network administrators typically employ a statically configured buffer allocation. However, this kind of fixed allocation typically requires over allocation in favor of higher priority traffic classes. The fixed allocation scheme is sub-optimal because these over-allocated buffers cannot be used for other lower priority traffic even when they are underutilized by the higher priority traffic classes for which the buffers were statically allocated.